Carburetor choke control device



.Dec. 24, 1940. J. SCHWEISS CARBURE'I'OR CHOKE CONTROL DEVICE Filed Aug.51, 1939 INVENTOR JOSEPH ScHwE|ss ATTORNEY Patented Dec. 24, 1940 PATENTOFFICE caanmm'roa cnoxr: CONTROL DEVICE Joseph Schweiss, St. Louis, Mo.,assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporationof Delaware Application August 31, 1939, Serial No. 292,869

7 Claims.

This invention-relates to choke control devices for internal combustionengine carburetors and more particularly to devices for convenientlyopening the choke valve against the resistance 6 of automatic chokemechanism. These devices are commonly called unloaders.

With the object in mind of preventing the inexperienced operator frominadvertently operating the unloading mechanism simultaneously 10' withthe starting motor, a mis-operation which frequently occurs inarrangements having both starting switch and unloading deviceinterconnected with the throttle, I have provided mechanism which willperform the unloading 15 function only after a period of crankingsuflicient to start an engine under normal starting conditions.

It is a further object of this invention to provide an "unloadingmechanism actuated by an 20 electro-magnet, the control of which may beeither independent of or dependent upon the throttle valve position.

Other objects and advantages will appear in the following descriptionand accompanying 25 drawing referring to which Fig. 1 is a somewhatdiagrammatic representation of a carburetor showing one form of myinvention. Shown diagrammatically therewith is a starting motor circuitand source of electrical energy.

30 Numeral I generally indicates a conventional downdraft carburetorhaving an air inlet 2 and a discharge outlet 3. For control of the airinlet an unbalance plate-type choke valve 4 rigidly attached to arotatable shaft 5 is provided. Shaft 35 5 extends outwardly from bothsides of the carburetor and on the far side extends into the automaticchoke mechanism housing 6. The automatic choke mechanism includes theusual thermoresponsive element 1 which yieldably positions 40 the chokevalve in accordance with the temperature in a manner described in thepatent to I. E. Coffey, #2,085,351. The discharge outlet 3 is controlledby a plate-type throttle valve 8 rigidly attached to the rotatable shaft9. Rigidly attached 45 to the near end of choke shaft 5 is a disc-likemember l having a radial projection ll. Adjacent member ID and looselymounted for rotation on shaft is a lever I2 pivotally attached at oneend to the armature l3 of an electro-mag- 50 net 14. At its opposite endlever l2 carries a pin l5 adapted to abut projection I I and therebyrotate member ID and consequently the choke valve toward an openposition as armature l3 descends.

55 Rigidly attached to the near end of throttle shaft 9 is an operatinglever 20 having a perforation at its outer end for attachment of a rod2| for remote manual control. A: spring 22 normally urges the throttlevalve tOVH'd a closed position. The cam surface 23 on lever 20 is pro- 5vided to close switch 24 as the throttle is moved toward an openposition. In the modification shown, electro-magnet I4 is connected witha starting motor relay switch l5 in the circuit I6 through parallelcircuit l6a. The circuit for starting motor I1 is indicated at It.Electrical energy is supplied by storage battery l9. Two switches areindicated in the starting relay circuit l6, namely, a suction operatedswitch 25 and the aforementioned throttle switch 24. A good l5 form ofstarting device for use in the present invention and which includes anadditional switch in the relay circuit controlled by generator out-- putis shown and described in a patent to I. E. Coiley No. 2,174,313.

To provide a predetermined delay of the functioning of the unloader andthereby permit sufflcient cranking with closed choke to start an engineunder normal conditions I have provided a U-shaped heat responsivebi-metallic element 26 series connected in the circuit I 6. A resistancecoil 21 in the ground lead from element 28 has been provided forbalancing. It will be understood that element 26 is so proportioned asto respond to the heat generated by the flow there- 30 through to spreadand connect parallel circuit Ilia to circuit after a predeterminedinterval during which circuit I6 is closed.

The operation of the device is as follows:

Upon starting a cold engine'the choke valve 4 will be yieldably held inthe position shown by heat responsive element 1. As the throttle leveris rotated clockwise to any position beyond that necessary to closeswitch 24, current will flow through circuit I5 thereby closing startingmotor 40 relay l5 to crank the engine. After the period required forelement 28 to respond sufliciently to connect parallel circuit I61; and,if within this interval the engine has not been successfully started,electro-magnet [4 will be energized and will open choke valve 4 in amanner described. If, however, the engine has been successfully startedwithin the interval, suction operated switch 25 will open to break thecircuit It at that point and remain open during operation of the engine.As the engine warms up the choke valve is free to rotatecounterclockwise in an opening direction independent of lever I2. I donot wish to be limited to the detailed description and structure shown,the use of all modifications within the scope of the appended claims iscontemplated.

I claim:

1. In combination, a carburetor having a choke valve, a throttle valve,mechanism for yieldably urging said choke valve toward a closedposition, an electro-magnet for moving, said choke valve toward an openposition against the resistance of said mechanism, an electrical circuitfor said electro-magnet, and means coacting with said throttle valve foropening and closing said electrical circuit.

2. In combination, a carburetor having a choke valve, a throttle valve,mechanism for yieldably urging said choke valve toward a closedposition, an electro-magnet for moving said choke valve toward an openposition against the resistance of said mechanism, an electrical circuitior'said electro-magnet, a switch in said circuit arranged to coact withsaid throttle valve, and a second switch in said circuit responsive toheat.

3. In combination, an internal combustion engine, a carburetor havinga-choke valve, an automatic choking device'ior yieldably urging saidchoke valve toward a closed position, an engine starting circuit, anormally disconnected branch of said circuit, an electrically operateddevice in said branch for moving said choke valve toward an openposition against the resistance of said choking device, and a delayedaction switch device, responsive to the flow of electrical currentthrough said starting circuit for connecting said branch thereto.

4. In combination, a carburetor having a choke valve, a throttle valve,automatic choke mechanism constructed and arranged to yieldably urgesaid choke valve toward a closed position, a starting motor controlcircuit, a normally disconnected branch of said circuit, a throttleactuated switch in said starting motor control circuit, anelectro-magnet in said branch for moving said choke valve toward an openposition against the resistance of said automatic choke mechanism, and aheat responsive element in said starting motor control circuit arrangedto connect thereto said branch circuit after a predetermined interval inwhich said starting motor control circuit is closed.

5. In combination, a carburetor having a choke valve, an automaticchoking device for urging said choke valve toward a closed position, anda manually controlled unloading device comprising an electro-magnetconstructed and arranged to move said choke valve toward an openposition against the resistance of said automatic choking device, anenergizing circuit for said electro-magnet,- a manually operated controlswitch in said circuit, and adelayed action switch device capable ofconnecting said electro-magnet into said circuit after a predeterminedinterval during which said manual switch'is closed.

6. In combination, an internal combustion engine, an engine startingcircuit, a carburetor having a choke valve, automatic mechanism formoving said choke valve toward a closed position, an electro-magnet insaid circuit constructed and arranged to move said choke valve toward anopen position against the resistance of said automatic mechanism undercertain conditions, a manual control switch in said circuit, andautomatic means functioning to maintain a broken starting circuit duringoperation of the engine.

'7. In combination, an internal combustion engine, an engine startingcircuit, a carburetor having a choke valve, an automatic choking devicefor yieldably urging said choke valve toward a closed positon, amanualcontrol switch in said starting circuit, an electro-magnet constructedand arranged to move said choke valve toward an open position againstthe resistance of said automatic choking device a thermostatic switch insaid starting circuit capable of connecting said electro-magnet in saidstarting circuit after a predetermined interval during which saidstarting circuit is closed, and automatic means tunetioning to maintaina broken starting circuit during operation of the engine.

JOSEPH SCHWEISS.

